Neutron activation analysis of rare earth elements in deep sea sediments from the Pacific Ocean and the Japan Sea

Seven REEs in the deep sea sediments from various regions /19 sites/ of the Pacific Ocean and the Japan Sea were determined with INAA. Regional variations of La/Yb ratio and Ce anomaly may reflect the relative contribution of the source materials in the formation of the deep sea sediments.     

Tritium concentrations of river water on northern and southern islands of Japan

Tritium concentrations were measured for river waters on two islands in Japan. Significant difference was observed on the distribution of tritium concentrations on both islands, the river water samples from the northern island had higher concentrations and the average was about twice compared to that from the southern island. Higher tritium concentration in precipitation and the larger area of the northern island would be responsible for higher tritium concentrations in river waters.     

Tritium concentration in fresh,brackish and sea-water samples in Rokkasho-Village,Japan, bordered by nuclear fuel cycle facilities

Summary In order to identify the concentration of tritium (³H) in areas of fresh, brackish and sea water, bordered by nuclear fuel facilities at Rokkasho-Village, Aomori, Japan, water samples were collected from 2001 to 2004 at six points in those areas. Concentration ranges of tritium in fresh river water, brackish lake and seawater samples were 0.60 to 1.1 Bq^. l^-1(mean value 0.79 Bq^. l^-1), 0.20 to 0.87 Bq^. l^-1(mean value 0.41 Bq^. l^-1), and 0.08 to 0.25 Bq^. l^-1(mean value 0.15 Bq^. l^-1), respectively. Relationships between tritium concentrations and salinity in the samples showed a clear negative correlation. Moreover, the seasonal variation of tritium in water from Rokkasho-Village was high in spring and low in fall.     

Plutonium in seawater of the Pacific Ocean

The present plutonium levels in the Pacific Ocean are summarized. The ^239,240Pu concentrations in surface seawaters in the early 2000s were in the range of 1.5 to 9.2 mBq·m⁻³ in the North Pacific and 0.8 to 4.1 mBq·m⁻³ in the South Pacific. There is no marked difference of surface ^239,240Pu distributions between the North and South Pacific subtropical gyres. The vertical profile of ^239,240Pu in the South Pacific was the similar pattern to that in the North Pacific, which is controlled by biogeochemical processes. The ^239,240Pu inventories (down to 2300 m) in the North Pacific are generally greater than that in the South Pacific, which reflects the geographical distribution of global fallout and effect of close-in fallout in the Marshall Islands.     

Tritium activity concentration along the Western shore of the Black Sea

The Black Sea tritium level was investigated in 33 places southward the Danube Delta covering about 360 km of the Black Sea Western Shore. Both surface (10 cm depth) and bottom (up to 20 m depth) water samples were collected. In the close vicinity of Danube Delta, the tritium activity concentration in the surface water was around 28 TU, which is almost the same as that of the Danube River waters, but it decreased to about 5 TU in the bottom water. This discrepancy slowly diminished wherein at about 120 km southward, the tritium content in both surface and bottom water reached almost the same constant value of 6.5 ± 2.3 TU. This value, about two and a half times smaller than that reported 17 years ago, remained almost unchanged for the last 240 km of shore up to the Turkish border.     

Effect of the deposition potential on the voltammetric determination of complexing ligand concentrations in sea-water.

The effect of the deposition potential on the determination of complexing ligand concentrations in natural waters was investigated by titration with Cu from sea-water samples originating from the North Sea and monitoring the labile Cu concentration after deposition at two potentials, viz., -0.05 and -0.7 V. The amount of deposited metal was measured by cathodic stripping voltammetry with ligand competition, using tropolone as the added ligand. It was found that the complexing ligand concentration detected decreased by more than 60% when the more negative deposition potential was applied. The data indicate that a significant fraction of the organic complexes of Cu in natural waters is electrochemically labile at negative deposition potentials and is not determined by anodic stripping voltammetry. The concentrations and conditional stability constants of the complexing ligands in the North Sea are similar to those detected previously in the Irish Sea.     

Concentration and distribution of 17 organochlorine pesticides (OCPs) in seawater from the Japan Sea northward to the Arctic Ocean

Seventeen classic organochlorine pesticides in surface seawater were studied in terms of their composition pattern as well as their distribution pattern in the areas covering the Japan Sea,Okhotsk Sea,Bering Sea,Chukchi Sea and Arctic Ocean.Their concentrations varied,but roughly two levels were seen with one ranging between 0.1 and 1 ng L-1 for most HCH isomers and the other lower than 0.1 ng L-1 for other chemicals.Of the 17 target compounds,HCHs were dominant with a total concentration percentage general...     

Tritium along the banks of the Danube and the Black Sea shore of Romania

Journal of Radioanalytical and Nuclear Chemistry - Determination of tritium along Danube River Banks, in shallow waters, from Bazia? to Sulina, led to an average value of 29 TU and to a slight...     

Plutonium isotopes in the Sea of Japan

Plutonium isotopes in the Sea of Japan were determined to assess radioactive contamination. Concentrations of ^239,240Pu in surface water of the Sea of Japan were maintained at a constant level over the past two decades in contrast to ¹³⁷Cs. A median value of surface ^239,240Pu in the Sea of Japan in this period was 5.6 mBq/m³ with the range between 2.1 and 14.0 mBq/m³, which is slightly higher than that in the western North Pacific. The vertical distribution of ^239,240Pu showed a surface minimum, a subsurface maximum and gradual decrease with increasing depth. The ²⁴¹Pu/^239,240Pu activity ratios in water columns were almost constant except for surface water. In regard to ^239,240Pu in surface water of the Sea of Japan, these findings suggest that rapid recycling of deeper plutonium occurs in the Sea of Japan due to deep convection in winter and biogeochemical processes such as particle scavenging and remineralization.     

239+240Pu and137Cs concentrations in salmon (Oncorhynchus keta) collected on the Pacific coast of Japan

Salmon (Oncorhynchus keta) samples were collected on the Pacific coast of Japan and analyzed for their^239+240Pu and¹³⁷Cs concentrations in six places, i.e., muscle, viscera, gill, gonad, skin and spine. The^239+240Pu concentrations in muscle ranged from 0.07 to 0.14 mBq/kg (wet) and had the lowest value among the six regions. The mean^239+240Pu concentrations in viscera, gonad and spine were more than 1 mBq/kg (wet_ while those in muscle and skin were one order of magnitude lower. The largest amounts of^239+240Pu were accumulated in gonad. The^239+240Pu/¹³⁷Cs activity ratios in all positions were lower than that of the global fallout ratio of 0.022, suggesting that¹³⁷Cs could be accumulated with greater ease than^239+240Pu in all positions and ratios of uptake differed remarkably from position to position. The total accumulations of^239+240Pu and¹³⁷Cs in salmon were 1.32 and 328 mBq/individual, respectively.     

Estimation of the sources of pelagic sediments from the South Pacific Ocean to the Antarctic Ocean

Gamma-irradiated L-α-alanine used in EPR-coupled dosimetry has a complex EPR spectrum at room temperature. Changing the temperature or other conditions of the irradiated samples leads to varied EPR spectrum, i.e., some components disappear and/or new ones are formed. We used both molecular mechanics (MM+) and semiempirical (AM1) methods to perform a theoretical investigation of the seven radical species that have been experimentally detected. We established their order of priority in the given simulation conditions (at 0 K, in vacuo). The formation stages advanced for these long-lived radical species were characterized by a theoretical determination of the reaction enthalpies.     

Ultra low level deep water <Superscript>137</Superscript>Cs activity in the South Pacific Ocean

We determined ¹³⁷Cs concentrations in deep water samples of the subtropical gyre in the South Pacific collected during the BEAGLE2003 cruise. This was done at an underground facility to achieve extremely low background γ-spectrometry, and we, therefore, obtained reliable values of ¹³⁷Cs activity in the deeper layers. ¹³⁷Cs activity in the layers between 2000 and 4500 m ranged from 7 ± 4 mBq m⁻³ to 25 ± 11 mBq m⁻³. The inventory of ¹³⁷Cs in the water column from 2000 m to the sea bottom was estimated to be 20 ± 8 Bq m⁻² to 94 ± 41 Bq m⁻² in this region.     

239Pu, 240Pu, 241Pu, 241Am, 137Cs,and 210Pb in seafloor sediments in the western North Pacific Ocean and the Sea of Japan: distributions,sources and budgets

Journal of Radioanalytical and Nuclear Chemistry - Vertical distributions of 239Pu, 240Pu, 241Pu, 241Am, 137Cs, and 210Pb concentrations, and 240Pu/239Pu ratios were determined in seafloor...     

Estimate of Fukushima-derived radiocaesium in the North Pacific Ocean in summer 2012

Distributions of radiocaesium (¹³⁴Cs and ¹³⁷Cs) derived from the Tokyo Electric Power Company (TEPCO) Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident in the North Pacific Ocean in the summer of 2012 were investigated. We have estimated the radiocaesium inventory in the surface layer using the optimal interpolation analysis and the subducted amount into the central mode water (CMW) by using vertical profiles of FNPP1-¹³⁴Cs and mass balance analysis as the first approach. The inventory of the ¹³⁴Cs in the surface layer in the North Pacific Ocean in August–December 2012 was estimated at 5.1?±?0.9 PBq on 1 October 2012, which corresponds to 8.6?±?1.5 PBq when it was decay corrected to the date of the FNPP1 accident, 11 March 2011. It was revealed that 56?±?10% of the released ¹³⁴Cs into the North Pacific Ocean, which was estimated at 15.3?±?2.6 PBq, transported eastward in the surface layer in 2012. The amount of ¹³⁴Cs subducted in the CMW was estimated to be 2.5?±?0.9 PBq based on the mass balance among the three domains of the surface layer, subtropical mode water, and CMW.     

Comparative studies on cadmium levels in the North Sea, Norwegian Sea, Barents Sea and the Eastern Arctic Ocean

Summary Dissolved and total concentrations of cadmium have been determined in the North Sea, Norwegian Sea, Barents Sea and the Eastern Arctic Ocean. The investigations started in 1975. The last sampling mission was in summer 1982. Trace metal determinations have been performed after contamination-free minimum pretreatment with differential pulse anodic stripping voltammetry (DPASV) at specially designed rotating mercury film electrodes. Distinct areas of trace metal pollution could be discovered. The coastal zones of Belgium, the Netherlands and Germany are significantly more polluted than the open ocean areas. In the open sea trace metal levels decrease from south to north, yielding the lowest results in the Eastern Arctic Ocean with about 10 ng/kg for Cd, thus reflecting anthropogenic pollution in the southern part of the North Sea. Cadmium levels in the areas mentioned above are distinctly higher than open Atlantic values.It is implicitly to be understood that the data given in this paper can be used as a reliable basis for the detection of anthropogenic changes in the North Sea within the coming years, particularly as reliable trace metal data from the mid seventies are extremely scarce.

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Vergleichende Untersuchungen über Cadmiumgehalte in der Nordsee, der Norwegischen See, der Barentssee und dem östlichen Arktischen Ozean

Zusammenfassung Gelöstes und Gesamtcadmium wurden in der Nordsee, Norwegischen See, der Barentssee und dem östlichen Arktischen Ozean bestimmt. Die Untersuchungen wurden im Jahre 1975 begonnen. Spurenmetallbestimmungen erfolgten nach einer kontaminationsfreien, einfachen Vorbehandlung mit der differentiellen inversen Pulsvoltammetrie an speziellen rotierenden Quecksilberfilmelektroden. Deutlich abgegrenzte Gebiete mit Schwermetallpollution konnten aufgezeigt werden. Die Küstenzonen Belgiens, der Niederlande und Deutschlands sind deutlich höher belastet als die offene Nordsee. In der offenen See fallen die Werte von Süd nach Nord, mit den geringsten Beträgen um 10 ng/kg Cd im östlichen Arktischen Ozean, ein Befund, der die anthropogene Pollution der Nordsee wiedergibt. In allen oben erwähnten Gebieten sind die Cd-Werte deutlich höher als im offenen Atlantik.Es kann davon ausgegangen werden, daß die Resultate dieser Untersuchungen als zuverlässige Basis für die Aufdekkung von anthropogenen Veränderungen der Belastung der Nordsee innerhalb der kommenden Jahre dienen können, dies um so mehr als zuverlässige Daten bis zur Mitte der siebziger Jahre äußerst selten sind.

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Dedicated to Prof. Dr. W. Fresenius on the occasion of his 70th birthday

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Awarded the prize of the Analytical Division of the Society of German Chemists     

Characterization and biotreatability of petroleum contaminated soils in a coral Atoll in the Pacific Ocean

Applied Biochemistry and Biotechnology - On Kwajalein Island in the Republic of the Marshall Islands, studies were conducted to characterize subsurface petroleum contamination and assess the...     

Tritium and carbon-14 concentrations around an incinerator for radioactive liquid scintillator waste

Activity measurements of 3H and 14C in several environmental samples around the incinerator for radioactive liquid scintillator waste at the Radioisotope Center, Kyushu University were carried out to estimate their levels. It was indicated that 3H and 14C concentrations in the atmosphere at 1 m from the outlet were about 0.2% of those estimated at the outlet, respectively. At 6 m away from the outlet, 3H concentration decreased to about one twentieth of that at 1 m and 14C concentration to background level. For soils and plants, 14C concentrations showed negligibly low values. The existence of these nuclides in particle form was not confirmed. It is considered that the result of the higher 3H concentrations as compared to 14C concentrations reflects not only the difference of the waste amounts of their nuclides, but also the discharge of 3H as moisture as well as water vapor.     

The main steroid alcohol from the Pacific Ocean holothurian Cucumaria fraudatrix

A steroid compound has been isolated from the holothurianCucumaria fraudatrix. On the basis of¹H and¹³C NMR spectra its structure has been established as 4,14-dimethylcholest-9(11)-en-3-ol.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center of the Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 185–187 (1986).     

Iridium in the Bering Sea and Arctic Ocean studied by neutron activation analysis

Neutron activation analysis combined with pretreatment based on anion-exchange was applied to the determination of Ir in the Bering Sea and Arctic Ocean seawaters. Separation and enrichment of Ir from seawater by a simple anion-exchange resin Bio-Rad AG1×8 was carried out prior to neutron activation. Ir concentrations in the vertically distributed Bering Sea and Arctic Ocean seawater samples were in range of 0.85–3.58 pg/l and 1.26–1.97 pg/l, respectively. The reagent blanks of the procedures were 0.42–0.60 pg Ir. It was found that Ir in the Bering Sea and in the Arctic Ocean displayed different types of vertical profiles.